While certain vaccines had long been linked to autism, the US vaccine court says vaccines containing mercury-based preservatives cannot cause autism on their own.

Many parents blame a combo vaccine used for measles, mumps and rubella (MMR) for causing autistic symptoms in their children. The US Institute of Medicine, however, has recurrently rejected such a link.

“It’s time to move forward and look for the real causes of autism,” said Alison Singer, the president of the Autism Science Foundation.

According to the federal court ruling, thimerosal, the mercury-based preservatives found in certain vaccines, does not place the child at an increased risk of developing autism.

“While we have great empathy for all parents of children with autism, it is important to keep in mind that, given the present state of the science, the proven benefits of vaccinating a child to protect them against serious diseases far outweigh the hypothesized risk that vaccinations might cause autism,” said Autism Speaks in a statement.